Filipino Nonito Donaire retained his IBF flyweight title on Sunday, stopping American challenger Raul Martinez in the fourth round.
Donaire (21-1) pummeled Martinez (24-1) with rapid punches to the head, sending him to the canvas for a fourth time in the bout before the referee stopped the fight 2:42 into the fourth.
Donaire floored Martinez twice in the first round and once in the second. In the fourth round, Martinez took a sharp left uppercut and fell backward, prompting referee Pete Podgorski to stop the match. The Filipino crowd roared, chanting Donaire's name.
In another bout, America's Brian Viloria (25-2) knocked out Ulises Solis (28-2-2) of Mexico with a right to the jaw in the 11th round to become the new IBF light flyweight champion.